Recording Device for Recording the Switch State of an Electromagnetic Switch Device

ABSTRACT

A recording device is for recording the switch state of an electromagnetic switch device. In at least one embodiment, the recording device includes a housing, in which a plunger is movably mounted. The plunger may be moved between two mechanical end positions, wherein the end positions of the plunger correspond to the switch states of the electromagnetic switch device. A sensor device is arranged in the housing by which it may be recorded in which of the end positions the plunger is and from which a corresponding electrical signal may be emitted. The sensor device is designed to be able to record the position of the plunger without contacting the plunger.

PRIORITY STATEMENT

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/EP2008/050157 which has anInternational filing date of Jan. 9, 2008, which designated the UnitedStates of America, and which claims priority on German patentapplication number DE 10 2007 002 176.5 filed Jan. 15, 2007, the entirecontents of each of which are hereby incorporated herein by reference.

FIELD

At least one embodiment of the present invention generally relates to adetection apparatus for detecting the switching state of anelectromagnetic switching device. In at least one embodiment, it relatesto a detection apparatus having the following features:

It has a housing in which a plunger is movably mounted.

-   -   The plunger can be moved between two mechanical end positions,        wherein the end positions of the plunger correspond to the        switching state of the electromagnetic switching device.

BACKGROUND

Electromagnetic switching devices, within the meaning of embodiments ofthe present invention, include electric contactors, isolating switches,line relays, power switches, etc. In the case of such electromagneticswitching devices, in particular electric contactors, it is necessary ina multiplicity of applications to detect the actual switching state ofthe electromagnetic switching device—as opposed to a control state ofthe electromagnetic switching device where applicable—in order to beable to analyze the switching state in another way.

According to the prior art, a detection of the kind takes place by wayof a detection apparatus as described above. In this case there isdisposed in the housing a mechanical switching contact which changes itsswitching state when the plunger is transferred from one end position tothe other end position. The switching contact is connected to ananalysis apparatus via lines, such that the switching position of theswitching contact and hence the switching state of the electromagneticswitching device can be detected by the analysis apparatus. Thedetection apparatus is usually a separate apparatus (called an auxiliaryswitch) which is different from the switching device.

The prior art approach usually works very well already. It is, though,capable of improvement. In particular, the reliability of the detectionapparatus can be increased.

SUMMARY

At least one embodiment of the present invention is directed to adetection apparatus in such a way that it operates with increasedreliability.

In at least one embodiment, a detection apparatus of at least oneembodiment has at least the following features:

-   -   A sensor apparatus is disposed in the housing, said sensor        apparatus being able to detect in which of the end positions the        plunger is located and to emit an electrical signal which        corresponds to said end position.    -   The sensor apparatus is embodied such that it is able to detect        the position of the plunger without touching it.

At least one embodiment of the detection apparatus ensures in particularthat the sensor apparatus is not exposed to the jerky, hard movements ofthe plunger. In particular it can therefore be embodied smaller andlighter in weight than in the prior art, and operate more quickly.

In at least one embodiment, it is possible for a pickup interface to bedisposed on the housing, the interface being accessible from outside thehousing and allowing the electrical signal that is emitted by the sensorapparatus to be immediately picked up as such. It is, however, preferredfor a conditioning circuit to be disposed in the housing, the circuitconditioning the electrical signal emitted by the sensor apparatus intoa message and outputting the message via a communication interface. Thislast-cited embodiment can be realized as an alternative or in additionto the direct pickup of the electrical signal emitted by the sensorapparatus.

A printed circuit board is preferably disposed in the housing and thesensor apparatus arranged thereon. This results in the production of thedetection apparatus being made simpler in manufacturing terms.

The sensor apparatus is preferably embodied as an electronic sensorapparatus which has no moving parts. By virtue of this embodiment it ispossible on the one hand to increase the reliability and service life ofthe sensor apparatus, and on the other hand to integrate and miniaturizethe sensor apparatus.

The housing and the plunger can be coordinated in such a way that it ispossible to identify visually from outside the housing in which of theend positions the plunger is located. In this case the switching stateof the electromagnetic switching device can not only be reported to theoutside by electrical or electronic device(s), but can also beidentified directly from the outside by a person.

It is possible for the detection apparatus to be part of theelectromagnetic switching device per se. As a rule, however, the housingof the detection apparatus is a different housing from the housing ofthe electromagnetic switching device, and the plunger of the detectionapparatus is usually a different plunger from the plunger of theelectromagnetic switching device. In this case the housing of thedetection apparatus can be fixed to the housing of the electromagneticswitching device. The plunger of the detection apparatus can beconnected to the plunger of the electromagnetic switching device in thiscase such that the plunger of the detection apparatus moves in concertwith the plunger of the electromagnetic switching device.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and details will emerge from the followingdescription of an example embodiment in conjunction with the drawings,in which:

FIG. 1 schematically shows the design structure of an electromagneticswitching device and a detection apparatus, and

FIG. 2 schematically shows an electrical block diagram of the detectionapparatus.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

According to FIG. 1, an electromagnetic switching device 1 is embodiedas an electric contactor. It has a coil 2 to which a switching currentIS can be applied. When the switching current IS is applied to the coil2, the latter attracts an armature 3. This is indicated by an arrow A inFIG. 1. When the switching current IS is interrupted, the armature 3moves away from the coil 2 due to a restoring spring force.

A plunger 4 is connected to the armature 3. Consequently, the plunger 4is also attracted by the coil 2 together with the armature 3. Owing tothe movement of the plunger 4, a load contact 5 (of which there is atleast one) is closed, with the result that a load current IL can flow.Conversely, the load contact 5 is opened again when the switchingcurrent IS is interrupted.

The electromagnetic switching device 1 typically has a plurality of loadcontacts 5, e.g. three, four or five load contacts 5. It is purely forthe purpose of greater clarity of illustration that only one loadcontact 5 is depicted in FIG. 1.

The embodiment of the electromagnetic switching device illustrated inFIG. 1 is not the only possible embodiment. The electromagneticswitching device 1 could alternatively be embodied as a power switch,for example. In this case the switching current IS is identical to theload current IL. The coil 2 in this case attracts the armature 3 if theload current IL becomes too great. Owing to the armature 3 beingattracted a breaker mechanism is released which moves the plunger 4 intoa position in which the load contact 5 remains open.

Irrespective of the specific embodiment of the electromagnetic switchingdevice 1, the electromagnetic switching device 1 has a housing 6 whichencloses the other aforementioned elements 2 to 5 of the electromagneticswitching device 1. Also irrespective of the specific embodiment of theelectromagnetic switching device 1, the position of the plunger 4corresponds to the switching state of the load contact 5 and hence tothe switching state of the electromagnetic switching device 1.

In order that the switching state of the electromagnetic switchingdevice 1 can be detected, a detection apparatus 7 is provided. Thedetection apparatus 7, which will be described in further detail below,can be part of the electromagnetic switching device 1. According to FIG.1, however, it is embodied as an add-on device which is placed onto theelectromagnetic switching device 1. According to FIG. 1, the detectionapparatus 7 therefore has a housing 8 which is different from thehousing 6 of the electromagnetic switching device 1. Furthermore, thedetection apparatus 7 has a plunger 9 which is different from theplunger 4 of the electromagnetic switching device 1.

In the present case, in which the detection apparatus 7 is embodied asan add-on device, the housing 8 of the detection apparatus 7 can befixed to the housing 6 of the electromagnetic switching device 1. InFIG. 1, this is indicated by snap-fit engagement hooks 10 which aredisposed on the housing 8 of the detection apparatus 7 and interact withengagement recesses 11 which are disposed on the housing 6 of theelectromagnetic switching device 1. However, the detection apparatus 7does not have to be fixed to the electromagnetic switching device 1 bymeans of a snap-fit connection. It can alternatively or additionally besecured in a different way, e.g. by way of screw connections.

The plunger 9 of the detection apparatus 7 is movably mounted in thehousing 8 of the detection apparatus 7. The plunger 9 of the detectionapparatus 7 can be connected to the plunger 4 of the electromagneticswitching device 1. Here, too, it is possible for snap-fit engagementhooks 12 to be disposed on, for example, the plunger 9 of the detectionapparatus 7 and to interact with engagement recesses 13 which aredisposed on the plunger 4 of the electromagnetic switching device 1.Another type of connection is also possible here, however. The essentialprovision is that the plunger 9 of the detection apparatus 7 movestogether with the plunger 4 of the electromagnetic switching device 1.

To the extent that the electromagnetic switching device 1 and thedetection apparatus 7 have been described hereintofore, the structurecorresponds to the structure that is generally known from the prior art.In particular, the plunger 9 of the detection apparatus 7 can be movedbetween two mechanical end positions. Owing to the connection of theplunger 9 of the detection apparatus 7 to the plunger 4 of theelectromagnetic switching device 1, the end positions of the plunger 9of the detection apparatus 7 correspond to the switching state of theelectromagnetic switching device 1.

According to an embodiment of the invention, however, a sensor apparatus14 is disposed in the housing 8 of the detection apparatus 7. The sensorapparatus 14 is able to detect in which of the end positions the plunger9 of the detection apparatus 7 is located. The sensor apparatus 14 isable to emit an electrical signal E which corresponds to the detectedend position. According to an embodiment of the invention, the sensorapparatus 14 is embodied in such a way that it can detect the positionof the plunger 9 of the detection apparatus 7 without touching theplunger 9 of the detection apparatus 7.

According to FIG. 2, the sensor apparatus 14 can be realized as a Hallsensor, for example. In this case, sections 15, 16 of the plunger 9 ofthe detection apparatus 7, which are located in the effective range ofthe sensor apparatus 14 in one of the end positions of the plunger 9 ofthe detection apparatus 7 in each case, must be embodied such that theyare magnetically different. For example, the sections 15, 16 can havemutually opposite magnetization.

In the case of the embodiment as a Hall sensor, the sensor apparatus 14detects the magnetic field. However, other embodiments are alternativelyconceivable. For example, the sensor apparatus 14 can be embodied as aninductive or capacitive proximity switch, or as a proximity switch whichis based on ultrasound. Alternatively again, the sensor apparatus 14 canbe embodied as an optical detection apparatus which detects in which ofthe end positions the plunger 9 of the detection apparatus 7 is locatedon the basis of transmitted or reflected light. The plunger 9 of thedetection apparatus 7 must, of course, have a corresponding design inthe case of each of these embodiments.

In the case of the above-described embodiments of the sensor apparatus14, the sensor apparatus 14 is embodied as an electronic sensorapparatus 14. It has no moving parts in this case. Alternatively,however, the sensor apparatus 14 could also have moving parts. Thiswould be the case, for example, if the sensor apparatus 14 were embodiedas a reed relay or as a switching element that is otherwisemagnetomechanically activated.

The detected switching state or, as the case may be, the electricalsignal E corresponding thereto, is usually required to be emittedexternally. In the simplest case a pickup interface 17 is disposed onthe housing 8 of the detection apparatus 7 for this purpose. The pickupinterface 17 is usually accessible from outside the housing 8 of thedetection apparatus 7. The electrical signal E can be immediately anddirectly picked up as such via the pickup interface 17; see FIG. 2 inparticular.

Alternatively or in addition to the presence of the pickup interface 17,it is possible for a conditioning circuit 18 to be disposed in thehousing 8 of the detection apparatus 7. The conditioning circuit 18 isconnected to the sensor apparatus 14. It conditions the electricalsignal E into a message N and outputs the message N via a communicationinterface 19. The communication interface 19 can be embodied for exampleas a bus interface, a point-to-point interface or a wireless connection.Like the pickup interface 17, it is preferably disposed on the housing 8of the detection apparatus 7 and accessible from outside the housing 8of the detection apparatus 7.

According to FIG. 1, a printed circuit board 20 is disposed in thehousing 8 of the detection apparatus 7. The components of the detectionapparatus 7, i.e. at least the sensor apparatus 14, are disposed on theprinted circuit board 20. If present, the conditioning circuit 18 isalso disposed on the printed circuit board 20. If applicable, the pickupinterface 17 and/or the communication interface 19 can also be disposedon the printed circuit board 20.

The electrical functionality of the above-described detection apparatus7 is entirely satisfactory. In addition, however, the housing 8 of thedetection apparatus 7 and the plunger 9 of the detection apparatus 7 canalso be coordinated in such a way that the end position in which theplunger 9 of the detection apparatus 7 is located can be identifiedvisually from outside the housing 8 of the detection apparatus 7. Thecoordination can be such that, for example, the plunger 9 of thedetection apparatus 7 is dimensioned and mounted in the housing 8 of thedetection apparatus 7 in such a way that the plunger 9 (see FIG. 1)projects out of the housing 8 of the detection apparatus 7 when the loadcontact 5 is open.

Alternatively or additionally, for example, an opening or a viewingwindow could be incorporated in the housing 8 of the detection apparatus7, such that a marker which is disposed on the plunger 9 of thedetection apparatus 7 is visible from the outside in exactly one of theend positions of the plunger 9 of the detection apparatus 7.

The housing 8 of the detection apparatus 7 is preferably coordinatedwith the plunger 9 of the detection apparatus 7 in such a way that it isalso possible visually to identify in which of the end positions theplunger 9 of the detection apparatus 7 is located when the housing 8 ofthe detection apparatus 7 is fixed to the housing 6 of theelectromagnetic switching device 1.

The above description serves solely to explain the present invention.The scope of protection of the present invention, in contrast, is to bedetermined exclusively by the appended claims.

Example embodiments being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the present invention, andall such modifications as would be obvious to one skilled in the art areintended to be included within the scope of the following claims.

1. A detection apparatus for detecting switching state of anelectromagnetic switching device, the detection apparatus comprising: ahousing; a plunger, movably mounted in the housing, the plunger beingmovable between two mechanical end positions, the end positionscorresponding to switching states of the electromagnetic switchingdevice; and a sensor apparatus, disposed in the housing, to detect inwhich of the end positions the plunger is located and to emit anelectrical signal corresponding to the detection, the sensor apparatusbeing able to detect a position of the plunger without touching theplunger.
 2. The detection apparatus as claimed in claim 1, furthercomprising: a pickup interface, disposed on the housing and accessiblefrom outside the housing, to allows the electrical signal, emitted bythe sensor apparatus, to be immediately picked up as such.
 3. Thedetection apparatus as claimed in claim 1, further comprising: aconditioning circuit, disposed in the housing, to condition theelectrical signal, emitted by the sensor apparatus, into a message andto output the message via a communication interface.
 4. The detectionapparatus as claimed in claim 1, further comprising: a printed circuitboard, disposed in the housing, the sensor apparatus being disposed onthe printed circuit board.
 5. The detection apparatus as claimed inclaim 1, wherein the sensor apparatus is embodied as an electronicsensor apparatus which has no moving parts.
 6. The detection apparatusas claimed in claim 1, wherein the housing and the plunger arecoordinated such that a location of the end positions the plunger isvisually identifiable from outside the housing.
 7. The detectionapparatus as claimed in claim 1, wherein the housing of the detectionapparatus is a different housing from the a housing of theelectromagnetic switching device and wherein the plunger of thedetection apparatus is a different plunger from a plunger of theelectromagnetic switching device, wherein the housing of the detectionapparatus is fixable to the housing of the electromagnetic switchingdevice, and wherein the plunger of the detection apparatus isconnectable to the plunger of the electromagnetic switching device suchthat the plunger of the detection apparatus moves together with theplunger of the electromagnetic switching device.
 8. The detectionapparatus as claimed in claim 7, wherein, when the housing of thedetection apparatus is fixed to the housing of the electromagneticswitching device, a location of the end positions the plunger isvisually identifiable from outside the housing of the detectionapparatus.
 9. The detection apparatus as claimed in claim 2, furthercomprising: a conditioning circuit, disposed in the housing, tocondition the electrical signal, emitted by the sensor apparatus, into amessage and to output the message via a communication interface.
 10. Thedetection apparatus as claimed in claim 2, further comprising: a printedcircuit board, disposed in the housing, the sensor apparatus beingdisposed on the printed circuit board.
 11. The detection apparatus asclaimed in claim 2, wherein the sensor apparatus is embodied as anelectronic sensor apparatus which has no moving parts.
 12. The detectionapparatus as claimed in claim 2, wherein the housing and the plunger arecoordinated such that a location of the end positions the plunger isvisually identifiable from outside the housing.
 13. The detectionapparatus as claimed in claim 2, wherein the housing of the detectionapparatus is a different housing from a housing of the electromagneticswitching device and wherein the plunger of the detection apparatus is adifferent plunger from a plunger of the electromagnetic switchingdevice, wherein the housing of the detection apparatus is fixable to thehousing of the electromagnetic switching device, and wherein the plungerof the detection apparatus is connectable to the plunger of theelectromagnetic switching device such that the plunger of the detectionapparatus moves together with the plunger of the electromagneticswitching device.
 14. The detection apparatus as claimed in claim 13,wherein, when the housing of the detection apparatus is fixed to thehousing of the electromagnetic switching device, a location of the endpositions the plunger is visually identifiable from outside the housingof the detection apparatus.
 15. The detection apparatus as claimed inclaim 6, wherein, when the housing of the detection apparatus is fixedto a housing of the electromagnetic switching device, a location of theend positions the plunger is visually identifiable from outside thehousing of the detection apparatus.